Mk II

The Mk II is an anti-personnel frag grenade that was developed in 1918 by John Browning for the US Army during World War I, replacing the failed Mk I. It has been nicknamed the "pineapple" for the cast iron grooves meant to enhance the grenade's grip and fragmentation, and it was in use with the US military as the standard issue grenade during World War II and then in the Korean War and Vietnam War. However, during the 1960s the grenade was gradually out of service, and in 1969 the US Navy was the last branch of the US Armed Forces to discontinue its use. However, US allies such as Israel, Brazil, Italy, the Philippines, Chile, and Argentina continued to use the grenade, which saw action elsewhere in the Suez Crisis and Six-Day War.